The interior spaces of railroad boxcars commonly are adjustably partitioned by heavy steel bulkhead doors which are rollably suspended from overhead roller tracks. Such roller tracks typically are welded to steel structural members at or near the upper ends of the side walls of a railcar, providing a pair of rolling surfaces extending longitudinally along the full length of the railcar. Rolling suspension of such bulkhead doors is typically provided by carriages having wheels positioned in rolling contact with the upper surfaces of the roller tracks, the carriage spanning the lateral width of the railcar. Commonly, such bulkhead doors have attached thereto a longitudinally extendable and retractable lading-engaging panel, such panel typically being pneumatically actuated through injection of pressurized air into an air bladder, such bladder being interposed between the lading-engaging panel and the bulkhead door. Injection of pressurized air into such an air bladder thrusts the lading-engaging panel away from the bulkhead door, moving the panel along a line parallel to the longitudinal axis of the railcar. Such motion presses the outer surface of the lading-engaging panel against cargo, preventing the cargo from shifting and moving during transportation. Common bulkhead door suspension carriages, such as cog wheel carriages (which are known to be adapted for rolling suspension of bulkhead doors and bulkhead door/lading-engaging panel assemblies) are often difficultly moveable, and often become misaligned and jammed. Also, frictional contact between cogs protruding from the wheels of a cog wheel carriage and cog wheel receiving apertures within overhead roller tracks, causes both the cog wheels and the roller tracks to prematurely wear out. The instant inventive door carriage provides smooth rolling motion of a suspended bulkhead door/lading-engaging panel assembly along the roller tracks of a railcar, and also provides for smooth rolling motion of the lading-engaging panel with respect to the bulkhead door. The instant inventive carriage also prevents jamming and reduces frictional wear. Such smooth rolling motion and prevention of jamming and frictional wear is provided by a rolling frame adapted for rolling suspension of a bulkhead door/lading-engaging panel assembly, the frame including roller tracks for suspension and separate rolling motion of the lading-engaging panel with respect to the bulkhead doors.